61 research outputs found
Platinum Inhibits LowâTemperature Dry Lean Methane Combustion through Palladium Reduction in PdâPt/Al2O3: An Inâ Situ Xâray Absorption Study
NSERCPeer ReviewedPalladiumâplatinum bimetallic catalysts supported on alumina with palladium/platinum molar ratios ranging from 0.25 to 4 are studied in dry lean methane combustion in the temperature range of 200 to 500â°C. Platinum addition decreases the catalyst activity, which cannot be explained by the decrease in dispersion or the structure sensitivity of the reaction. Inâ
situ Xâray absorption nearâedge structure and extended Xâray absorption fine structure spectroscopy measurements have been conducted for monometallic Pd, Pt, and 2:1 PdâPt catalysts. Monometallic palladium is fully oxidized in the full temperature range, whereas platinum addition promotes palladium reduction, even in a reactive oxidizing environment. The Pd/PdO weight ratio in bimetallic PdâPt 2:1 catalysts decreases from 98/2 to 10/90 in the 200â500â°C temperature range under the reaction conditions. Thus, platinum promotes the formation of the reduced palladium phase with a significantly lower activity than that of oxidized palladium. The study sheds light on the effect of platinum on the state of the active palladium surface under lowâtemperature dry lean methane combustion conditions, which is important for methaneâemission control devices
Ruthenium particle size and cesium promotion effects in FischerâTropsch synthesis over high-surface-area graphite supported catalysts
Cu-ZSM-5 Zeolites for the Formation of Methanol from Methane and Oxygen: Probing the Active Sites and Spectator Species
Deactivation Behaviour of Nickel Catalysts used for Internal Reforming in Molten Carbonate Fuel Cells
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